porphyrize

Century Dictionary and Cyclopedia

1. To cause to resemble porphyry.
2. To grind with a muller upon a slab of porphyry, as painters' colors. Also spelled porphyrise.

Wiktionary

1. v. transitive To cause to resemble porphyry; to make spotted like porphyry.

GNU Webster's 1913

1. v. To cause to resemble porphyry; to make spotted in composition, like porphyry.